Question

AJUTOR URGENT VA ROG , DAU COROANA
FARA RASPUNSURI AIUREA!!​

Answer 1

Explicație pas cu pas:

a) 21 este divizibil cu (2x+1) => (2x+1) este divizor al lui 21

(2x+1) ∈ {1;3;7;21} |-1

2x ∈ {0;2;6;20} |:2

x ∈ {0;1;3;10}

$x \neq 0 \implies \bf M = \{1;3;10\}$

cardM = 2³ = 8 => M are 8 submulțimi

Ø, {1}, {3}, {10}, {1,3}, {1,10}, {3,10}, {1,3,10}

b)

(2y-4) | (3y+5) <=> 2×(y-2) | 2×(3y+5)

(y-2) | (3y-5) <=> (y-2) | [3×(y-2)+11]

(y-2) | 3×(y-2) => (y-2) | 11

(y-2) ∈ {1; 11} |+2 => y ∈ {3; 13}

$\bf N = \{3; 13\}$

$\implies \bf M \cap N = \{3\}$